Networks, such as local area network (LAN) architectures frequently require the transmission of power, data and control signals to remotely located devices such as voice over internet protocol (VoIP) telephones or wireless local area network (WLAN) devices. Traditionally, in order to supply power along with the transmitted data signals, LAN architectures required multiple wired connections to the remote devices. For example, WLAN devices were able to communicate Ethernet data signals via category three (CAT-3) or category five (CAT-5) twisted pair wire and to receive power from a second cable connected to a power source, such as a wall socket or a battery. Additional cabling was necessary for communication of management and control signals.
Earlier systems implemented a practice of applying power to a remote 10/100 Base T Ethernet based device over unused pairs of conductors in a 10/100 Base T Ethernet cable. The present system extends the scope of earlier implementations by adding out of band communications to the unused pairs to manage and control the remote device. Specifically, the present system extends the described power over Ethernet scheme by modulating a serial bit-stream over the same unused pairs in a fashion that is compatible and interoperable with existing power over Ethernet schemes. This process solves the problem of requiring multiple connections to a remote device for power, primary network connection and console interface.
Eliminating the need for separate power, data and control wiring simplifies the installation and management of network devices, such as VoIP telephones or wireless access points, and can reduce the cost of installation. Therefore, it is desirable to transmit management and control signals over the same cabling that currently provides power and network connectivity while only requiring the integrity of the physical layer.